Question: Solve for $x$ and $y$ using substitution. ${6x+5y = 3}$ ${y = -x-1}$
Answer: Since $y$ has already been solved for, substitute $-x-1$ for $y$ in the first equation. ${6x + 5}{(-x-1)}{= 3}$ Simplify and solve for $x$ $6x-5x - 5 = 3$ $x-5 = 3$ $x-5{+5} = 3{+5}$ ${x = 8}$ Now that you know ${x = 8}$ , plug it back into $\thinspace {y = -x-1}\thinspace$ to find $y$ ${y = -}{(8)}{ - 1}$ $y = -8 - 1$ $y = -9$ You can also plug ${x = 8}$ into $\thinspace {6x+5y = 3}\thinspace$ and get the same answer for $y$ : ${6}{(8)}{ + 5y = 3}$ ${y = -9}$